+++++++++++++++++++ From: "Ron D' Eau Claire" To: Subject: RE: [Elecraft] K2 - Strong Signal Interference Date: Sat, 26 Jan 2002 21:10:00 -0800 Dave, K7EL asked: > His signal was thumping in all over the 20M band it seemed... > Any thoughts on the best way to deal with a *very* strong > adjacent signal on > the K2? I'd say that the first thing to do is to turn off the preamp if you are using it and perhaps turn ON the Attenuator. I live in a fairly quiet area and my K2 will seldom, if ever, lose any sensitivity by having the preamp off and the attenuator on at 20 meters. I use the preamp at times on 10 meters, but that's just about the only band where my doublet antenna doesn't provide more than enough signal for the K2 to hear all that it is capable of hearing. Checking to see if turning the preamp off or turning the attenuator on is hurting the sensitivity is easy. Just tune to a clear spot on the band where there are no signals, and then disconnect the antenna. If the background noise drops, then the K2 is hearing all that it can possibly hear. Adding a preamp or turning off the attenuator will do absolutely nothing to help it hear a weak signal, but it will reduce the K2's ability to reject strong local signals. If the noise level drops when you disconnect the antenna, the sensitivity will be entirely determined by the band noise. That's why more r-f gain in the K2 won't help dig out a weak one. Of course, you want to do this on the narrowest filter setting you might use since narrowing the bandwidth reduces the band noise. That's why you can hear weak ones better with narrow filter settings. If the other station is still 'all over the band' with the attenuator on, I'd listen carefully with a short, makeshift antenna that brings his signal down to a mere S9 or so. You might find that he is STILL "all over the band", meaning that he has key clicks or spurs or is making hash. In that case, it may well be coming from his transmitter, not being created in your receiver. I have heard a number of stations with more than one signal on the band - one nice and clean and the other rough and unstable. And some of them were halfway across the country. What's happening is that a stage is oscillating or something else has gone wrong at the transmitter. Unfortunately, too many Hams assume that if their rig is making r-f it is working fine. They never check to see if it is transmitting a clean signal unless someone knocks on their door. And even then they might take some convincing . Ron AC7AC ++++++++++++++++ Date: Sat, 26 Jan 2002 19:33:55 -0800 From: lhlousek Subject: Re: [Elecraft] K2 - Strong Signal Interference To: David Castor , elecraft at mailman.qth.net The simplest and best thing to do is to turn off the preamp and turn on the attenuator. These cut the sig at the front end of the rig and do the most in terms of improving BDR and IMDDR. Turning down the "RF" gain won't really help much because it isn't really RF gain. It is IF gain which comes after the damage has been done. Lou W7DZN +++++++++++++++++ From: N2EY at aol.com Date: Sun, 27 Jan 2002 10:07:03 EST Subject: Re: [Elecraft] K2 - Strong Signal Interference To: dpcastor at attbi.com, elecraft at mailman.qth.net In a message dated 1/26/02 9:42:06 PM Eastern Standard Time, dpcastor at attbi.com writes: > I tried a variety of filter/AGC/RF Gain settings, but I'm not sure I figured > out what would work the best. > These steps maximize strong-signal handling capacity: Control volume with RF gain control only - use as little as possible AF gain all the way up AGC OFF Preamp OFF Attentuator ON 73 de Jim, N2EY ++++++++++++++++++++ Date: Sun, 27 Jan 2002 13:53:10 -0500 To: "David Castor" From: Dave Gingrich K9DC Subject: Re: [Elecraft] K2 - Strong Signal Interference Cc: At 15:26 1/26/2002 -0800, David Castor wrote: >His signal was thumping in all over the 20M band it seemed. I was able to >work him by turning down the RF gain. But I had difficulty in working >stations within a few kHz of this strong signal. I'm sure any other rig >would have had a similar problem, if not a worse problem with this. Do you have the Noise Blanker? Make sure it is OFF. ================================================ Dave Gingrich, K9DC - Indianapolis, Indiana USA +++++++++++++++++++ From: "David Castor" To: Subject: Re: [Elecraft] K2 - Strong Signal Interference Date: Sun, 27 Jan 2002 15:08:12 -0800 Thanks to all for the feedback on this question. Just to clarify my first post, my neighbor was running QRP - no problem with his signal. We're just really close. I was able to work other stations once I got about 5-6 kHz away - I could still hear him, but could work other stations. I think the situation was just very demanding for any receiver. When I talked with my neighbor, he was having similar problems with his receiver as well. I was just interested in the collective thinking on how best to attack the problem should it happen again. 73, Dave - K7EL ++++++++++++++++++ Date: Mon, 19 Aug 2002 22:00:11 +0200 From: Heyder.Family at t-online.de (Norbert Heyder) To: elecraft at mailman.qth.net Subject: [Elecraft] K2 receiver trouble with local FM Broadcast Stations If you will ever have trouble with the the K2 concerning local Broadcast FM Stations making receiver noise on 14.060Mc or somewhere else, you should check the nut securing the key input jack on the rear. I had such problems as soon as the paddle was connected to the K2. The reason: The nut of the jack made no contact with the rear panel although the grey paint was removed there! I just tightend the nut a bit more until it made a "solid" contact with the rear panel. That completely removed the noise. gl es 72 de Bert DL8BDF K2 #433 ++++++++++++++++++